The swallow, sand martin and house martin are collectively known as hirundines, which means swallow like flight, derived from the Latin for a swallow, hirundo.
The first to arrive is the sand martin in late March, then the swallow in mid April and finally the house martin in late April. It`s a remarkable sight to see a swallow fly over a barn door, or enter an outhouse through a broken pane, without breaking speed, and only folding its wings at the very last minute. The preferred habitat of the swallow is open grassy farmland whereas the sand martin is found not too far from water. Sand martins nest in colonies, gradually excavating a tunnel in the face of a sandy riverbank and returning to the same colonies each year. They readily take to artificial nest structures erected over any body of water such as the one built for them at Seaton Wetlands. The water gives them some protection from ground predators.
Both the swallow and the sand martin feed on insects close to the ground and in the lower part of the sky, whereas the house martin feeds higher up in the middle part of the sky. House martins also nest higher, in colonies on the outside of buildings. This zoning of their different preferences for feeding and for nest sites, allows each species to exploit different habitats within the same geographical range.
The last aerial acrobat to arrive in May is the swift. They live in the upper sky feeding on different types of insects and tiny spiders compared to the hirundines. Their nests are in holes in buildings located much higher than the house martin, such as in gaps in the roof of a house or in a church tower. In some Italian towns, swift towers were built to attract them and then the chicks harvested as a delicacy. Now, in more enlightened times, the same towers are listed buildings and the same towns celebrate their swifts and conserve them. The only enemy of the swift is the hobby falcon which can match them for speed and agility. They have few competitors for food, which is probably why they are found in every country from Western Europe to China.
Swifts spend the summer in the skies above the Central African rainforests and arrive with us having never touched a solid surface for a year. Unlike the hirundines, they are unable to perch. Swifts have four toes forward in two pairs, with the outer toe of each pair able to rotate backwards. They are adapted to cling on to a vertical surface with considerable force before entering the nest hole. The legs are very short and if they fall to the ground, then they find it difficult to get airborne again. Their scientific name is Apus apus, which translates to no foot, no foot.
Swifts only breed when they are two years old, but remarkably, the non- breeders make the journey all the way from Africa to find a mate and a nest site. They are known as “bangers” because of the noise they make with their chest and forewings as they hit a building with such force while investigating a suitable nest hole. The following year the pair unite at the nest hole found in the previous year, and do the same each year afterwards.
If you have have any of these species breeding at your property this summer, then please email your postcode with the number of occupied nests to sidvalleybiodiversity@yahoo.com. This will greatly help in our records to determine their status in the Valley.
Mick Street
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